Hydraulic service jack



Allg- 5, 1952 E. H. scHuL'rz HYDRAULIC SERVICE JACK 2 SHEETS-SHEET 1 Filed Jan. 19, 1948 Patented Aug. 5, 1952 UNITED STATES PATENT OFFICE HYDRAULIC SERVICE JACK l Edward H. Schultz, Milwaukee, Wis.

Ap'plicationianuary 19, 194s, ys=rial41 `\1o.'3,047l

1 This invention relates draulic service jacks.

It is a general object of the present invention to provide an hydraulic service .jack having a novel leverage arrangement, which is so designed that the saddle supporting and lifting members swing upwardly in a manner similar to the boom on a power shovel or crane, stresses in said 'lifting members being taken in compression and tension to produce maximum strength in proportion to the weight of the structural parts.

A further object of the invention is to provide a jack as above described, wherein the leverage arrangement makesV it possible for the jack to handle its full ratedcapacity at any point in the range of movement thereof. This is to be distinguished from the conventional jack which can handle only about half of its rated capacity in its low position, and which does not reach its rated capacity until near the middle of itsl lifting range.

A further object of the invention is to provide an hydraulic service jack which is portable and easy to handle, but nevertheless sturdy enough to lift objects up to two tons if required. vDue toits compact size, itis small enough to be accommodated in the trunk of a passenger car, a convenience to garages rendering road service.

A further object of the invention is to provide an hydraulic jack wherein the hydraulic pressure in the system is practically uniform throughout the lifting range. Thus, ,a -safety valve for automatically by-passlng hydraulic fluid to the reservoir when an overload is applied is rendered accurate throughout the rangerof lifting movement. In the conventionaljack where the hydraulic pressurevaries, safety valves are not accurateand therefore additional bulb must be employed in the jacks. l 'Y A more specific object of the invention is to provide jacksl wherein the hydraulic ram swings with the lifting levers and saddle during Vraising and lowering movement to maire it possible to secure the advantages above describel..v

A further object of the invention is to provide a lifting jack whereinjthe operator may select any one of three lifting speeds,` the manual effort required being directly proportional tothe lifting speed selected. Thus, theoperator may select a speed to suit his particular preference. For example, a boy may require the use of a slower speed because of the lower vamount of effort necessitated. whereas, a man may prefer to do the same job faster. f

A further, more specic obiect of the invention is to provide-a construction as above deto improvements in hy- 7Claims. (Cl.254 -10)" 2' scribed, wherein the selection of pumping speeds is accomplished by a slight rotation of the operating handle in one direction or the other.

` A further object ofthe invention is tor provide a jack asabove described, wherein the pump has increased efficiency to render relatively short strokes of the handle effective in raising the saddle. Thus, it is possible to use the jackeiiiciently under low vehicles.`

A further lobject of the invention to'provide an improved hydraulic jack wherein the hydraulic pressure release is rendered relatively simple by placing such release under the control of the handle rotation, and wherein the release valve is arranged-to close automatically whenever 'the handle is raised.

Other objects of the invention'are to provide an hydraulic service jacklwhich resists wear and therefore has long lasting efficiency, which isvrelatively'simple-and inexpensive to manufacture,

which is neat'in appearance, and which is otherwise well adapted for the purpose described.

1 With the above and other objects in View, the

inventionV consists; ofy the improved hydraulic service'jack, .and allits parts and combinations,

thereof; l n

In'the accompanying drawing, illustrating one complete embodiment of the preferred form of the invention, in which the same reference numerals designate the same parts in all of the views:

Fig. 1 is a perspective view of the jack showing the saddle in elevated position, part of the handle being i broken away; Fig. `2 is a vertical longitudinal sectional view of the'improvedjack with the saddle in lowered position;`

FigJ is a top view of the jack in collapsed position, parts beimr broken away. and other parts being broken .awayand` shown in horizontal section; L

' Figfi isv a perspective view of the back end of the jack to show the speed selector arrangement;

Fig. 5 is a fragmentary plan view looking down on the back end of the jack, the handle being removed and parts being broken away and shown in section; and

Fig 6 is an end elevational view lookingkat the opposite: end ofthe jack from'the end shown in Fig.` 5, `with parts broken away and shown in verticalv section. y

Y The frame and. pump mechanism Referring morefparticularly to the drawings, there are side' plates lll which are spaced apart to accommodate the operating mechanism. Extending transversely of the plates at the forward end thereof is a front axle I I and rotatably mounted on the ends of the axle are front Wheels I2. At the opposite end the plates are maintained in spaced condition by a pump piston retaining bar I3, and projecting laterally from the outer sides of the plates I at said end are brackets I4 to which casters I5 are pivoted Von bolts I6. the casters being equipped with caster wheels I1. Secured between the spaced plates I0 at the rear end of the frame is a pump body I8, the latter including a removable cover I9. Within the upper portion of the pump body is a main reservoir 28 (see Fig. 2) which is in communication with side reservoir portions 2| (see Fig. v3). In the lower solid portion of the pump body I8 are laterally spaced bores 22 and 23, one of said bores, such as the bore 22, being of larger diameter than the other; Slidable'in the bores 22 and 23 are pump pistons 24'and -25 respectively which are hollow to accommodate coil springs 26 and 21. The outer end of each piston is closed as is clear from Fig. 3, and is adapted to'prcject externally of the pump body from itsbore.y The closed end of each piston forms a seat for one end of the coil spring therein, and the other Vend ofthe coil Vspring is adapted to be seated in the inner end of the respective bore 22 or 23. TheV saldinner ends of the bores are interconnected Vby :af-transverse duct28.' i

Extending between the side reservoir portions 2I is a transversely extending duct 29 which com'- municates at a point intermediate its length with a vertical duct 30 (see' Fig. 2). The upper endof the vertical duct 30 'communicates witha larger duct'portion 3| so that there is an annular shoulder 32 therebetween'forming a seat for a check ball 33. Abovel the check ball 33 the duct portion 3| is in communicationfwith thepassageway '28 connecting the'forward ends of the piston bores 22 and 23. Above this point, the'duct portion 3l connectsA with a still larger duct portion 34,- there being an annular shoulder'35 formedbetween said two duct portions and forming a seatfor a check ball 36, the latter being located above'the passageway 28. The upper endof the duct 34 is adapted tobe closed by a removable plug 31.

Extending from one' side'of the'duct 34 and communicating with the inner end of Aa bore 36A is a short duct 39. The inner end of the bore 38 forms a seat for a relief valve 49. The latter is mounted on the innerend'of 'a stem 4I; andfthe latter projects through a suitable-packing 42 to a point outside of the'valve body Where nutsV 43 are threaded thereon." A spring 44 normally urges the relief valve to closing position to prevent the flow of oil from thelduct 34 through the duct 39 andpassageway`45into the reservoir-28. The

spring tension may'beadjusted 'by means of a nut 46 and is preferably adjusted to permit opening ofthe valve when pressures exerted thereon exceed 6,800pou'nds per 'square inch;

The hydraulic ram 4 jecting from the piston through the forward end of the ram cylinder.

In order to provide for proper communication between the pump and the hydraulic ram, a novel arrangement has been provided which is illustrated more particularly in Fig. 3. The pivot shaft 5I is provided with an annular groove 56 which is so located as to be in communication With the outer end of the oil duct 49, there being suitable oil seals 51 land 58 on each side of the groove 56. v A similar annular groove 59 is connected by an obliquely extending internal bore 60 with the annular groove 56, as is clear from Fig. 3. The groove 59 is located in a solid portion of the ram base'Y 50 and there are oil seals 6I on each side of the annular groove 59. The groove 59 in turn communicates with the end of a duct 62 leading into' the cylinder 53. It is thus apparent that oil can flow to and from the hydraulic cylinder and that there is no interference as a result of the pivotal mounting for the cylinder and no necessity for employing flexible conduits.l

The lifting members and saddle The outer end of the ram plunger 55 is provided with a head 63 (see Fig. 2) which has a bore through which a transverse shaft 64 extends, the latter having its endsv secured in opposite sides of .a U-shaped supporting bracket 65 for a saddle 66. Also pivoted on said shaft 64 as at 61 are the outer ends of tie rods 68. The inner ends of said tie rods 68 are pivoted on a shaft 69 which extends transversely between the side plates I0 `above the pump body. Another pair of tie rods 10 have their inner ends pivoted on a shaft 1I which extends transversely between the side plates I9 adjacent the pump body. The outer ends of the tie rods 18 are pivotedas at 12 to a shaft 13 which extends transversely of the saddle bracket 65 (see Fig. 6). Connected to the shaft 13 between the pivotal connection 12 byfmeans of a U-strap 14 is one end of each of a pair of coil springs 15. The other ends of the springs are connected to studs 16 projecting from the side plates I0 (see Fig. 3). The tie rods 68 and 19 serve in conjunction with the ram as lifting levers.

The handle confz'ol'and speed selector At the rear end of the side plates, and extending transversely thereof, is a handle fulcrum member 11 pivotal on end trunnions 18. The fulcrum member has an intermediately located cylindrical projection 19 formed with a bottom flange 80. A handle member 8| has its lower end inserted into the upper end of a sleeve 82 and secured in position by a bolt 83. Intermediate the length of the sleeve is an intern-al annular shoulder 84 which is adapted to abut the outer end of the cylindrical extension 19. A il'angedre'taining ring 85, which coacts with the opposite side of the annular shoulder 84 is connected by a bolt 86 with a cylindrical extension 19. The result of this arrangement is that the handle and lower end sleeve may be rotated on the extension 19, and also the handle may be pumped up and down on the pivot shaft 18.

Projecting from the lower side of the sleeve 82 is a pump operating lever 81 having its lower end in the form of la T as at 88. By referring to Fig. 4, when the handle is in the normal position shown, the T-shaped lower end of the lever 81 will engage both of the pump pistons 24 and 25 to operate said pistons simultaneously. When the handle is rotated a slight distance in one diand between nuts 95 and 96 on the other of jsaid bolts. When either of said levers, 89 or 95 is rocked to the opposite position from that shown in Fig. 5, it will push outwardly ionthe'nuts 43 which are on the outer end ofn therelief valve stem 4I and cause opening, of 1said valve to release the oil pressure and allow theoilto' flow fromthe cylinder 53 back into the reservoir 2B. y

Operation In use of the jack, if the user desires to raise the jack from the position of Fig. 2 to the position of Fig. 1 at a relatively high rate of speed and does not mind the extra effort required, the handle 8| is yrotated in a clockwise direction, referring to Fig. 4, so that the vT-shaped end 88'of the lever'l contacts the rend of the piston 24 only. If the operator'does not-care about Vthe speed but wants to reduce the amount of manual effort required, then the handle 8| is rotated in a counterclockwise direction, referring to Fig. 4, to engage the piston only. If the handle is maintained in the position of Fig. 4, it will engage both pistons simultaneously to give the fastest lifting speed with, however, the greatest amount of manual effort.

With whatever speed is selected the plunger is pumped up and down, which action aided by the springs 26 and 2 which are within the pistons causes the pistons to reciprocate in and out. Referring to Fig. 3, when the spring 21 pushes the piston 25 to the position of said figure, oil is sucked from the reservoir pocket 2l into the ducts 29 and 35; The suction stroke causes the check 33 to be lifted t0 admit oil into the duct portion 3 i, duct 28, and piston bore 23; On inward movement of the piston 25 the check ball 33 stays closed and a charge of oil is forced past the check ball 35, and then through the ducts 34, 49, 56, 50, 59 and 62 to the inner end of the ram cylinder 53 to cause an outward push on the ram piston 54. By continued pumping, the ram plunger 55 will be moved outwardly. During such movement the tie rods 58 and 10 pivot on their ends and the saddle is gradually swung upwardly to the position of Fig. 1 against the tension of the springs l5. During such movement stresses are taken both in compression and tension producing the greatest possible strength in proportion to the weight of the structural parts. Also, due to the novel construction, the hydraulic pressure is substantially uniform throughout the range of movement so that the jack is able to raise a full capacity load beginning at lowest starting position of the saddle. During such movement, if any overloading should take place, the relief valve 40 will open to by-pass oil into the reservoir 20. Due to the fact that the hydraulic pressures are uniform throughout the range of movement, the relief valve may be adjusted accurately and proper performance is assured.

To lower the jack it is merely necessary to rotate the handle to a position to contact one or the other of the levers 89 or 90. By pushing downwardly slightly after such rotation, a pull is exerted on the stem 4l of the valve 40 to re- 6 Y lease the hydraulic-pressure andjpermitthe oil to flow 'back vinto Ithe Jreservoir '20 under the weight of the load, the return also being aided bythespring'l'. j I

Due to the eiciency ofthe 'pump Vdesign a relatively short stroke lofthe handIeissuIliGient to operate the jack.l This enables the jack' to'be used successfully under diiiicult conditions where the vehicle has alow overhang`. AV The'release valve 40, dueto the actio'nof vthe spring V44, closes automatically as soon as Vthe'handle 8| is raised or released. l

Variousk changes andmodiiications may be made withoutdeparting from the spirit of the invention, and-all ofsuch changes are contemplated, as may come within the scope of the claims. Y

What I claim is:

1. In an hydraulic Ijacl; havinga supporting frame and having an 'elevatinglsaddle rods pivotally connected ybetween sadfraine ands/addle for swinging movement relative .tofsaid frame, an hydraulic ram having a plunger portion pivotally connectedto ,'said saddle' andfhavinga cylinder portion provided'witha,lol n 'ehavingf a. pivot bore extending transversely' therethrdugh, I an hydraulic pump on said fram-e having afpivot extension provided withv a `tran's'vensepivfi't bore, there being a duct for hydraulic ,fly A Avextending from said pump to said bore of s a'idpivot extension and there being a duct extending fromthe bore Vof the cylinder base `tojsai'd cylinder', and a pivot pin supported trans'v'erselyHw 'the fram'eand extending through `said bores', d. pin VY.h'a'vinfg fluid ducts therein shapedl and positionedtoltransmit uid from the'p'ump extensin'. duct 'to the cylinder base duct in any position offpivo'tal movement of said cylinderj s y,

2. In an hydraulic jack having a supporting frame and having an elevating saddle, rods pivotally connected between said frame and saddlefor swinging movement relative t'oisaid.frame, an hydraulic ram having a plungerfportionpivotally connected to said saddle and'ha'vinglfa cylinder portion provided with a basehavinga .pivot bore extending transversely therethrough, "an hydraulic pump on said frame,.apivotextension on said frame provided with a transverse pivot bore, there being a duct for hydraulic fluid extending from said pump within said pivot extension to the bore thereof and there being a duct extending from the bore of the cylinder base to said cylinder, and a pivot pin supported transversely of the frame and extending through said pivot bores, said pin having fluid ducts therein shaped and positioned to transmit hydraulic fluid from the duct in the pivot extension on the frame to the cylinder base duct in any position of pivotal movement of said cylinder.

3. In an hydraulic jack having a supporting frame and having an elevating saddle, rods e pivotally connected between said frame and saddle for swinging movement relative to said frame, an hydraulic ram having a plunger portion pivotally connected to said saddle and having a cylinder portion provided with a base having a pivot bore extending transversely therethrough, an hydraulic pump on said frame, a pivot extension on said frame provided with a transverse pivot bore, there being a duct for hydraulic uid extending from said pump within said pivot extension to the bore thereof and there being a duct extending from the bore of the cylinder base to said cylinder, and a. pivot pin supported transversely of the frame and extending through said 7 pivot bores, said Apivot :pin having an annular groove -in registration with theduct of .the pivot extension on the frame and having an annular groove in registration with the cylinder base duct and there being an internal duct in said pin' connecting said two annulargrooves. I

,4- In an hydraulic jackhaving 4a supporting frame and ,having fan elevating saddle, rods pivotally connected between said frame and saddle for, swinging movement relative to ksaid frame, an hydraulic ram having aplunger portion pivotally connected to said saddle and having a cylinder portion provided with a base having a pivot bore 4extending transverselytherethrough, an hydraulic pump on said frame, a pivot extension on said Atrarne .providedv with' a transverse pivot bore, there being a duct for hydraulic fluid .extending from said pump within lsaid pivot extension to the bore thereof andthere beinga duct extending ,from 4the bore of the cylinder base to said cylinder. 'anda wpivot pin supported transverselyof'the frame and extending through said pivot boresjsaid pivot pin having an annular groove in registratim withthe v,duct .of the pivot extension on the frame and having an annular groove in registration with the .cylinder base duct and there being an internal duct extending obliquely through said pin from one sideA of one annular groove to the opposite side of the other annular groove.

5. In an hydraulic jack; V a supporting frame; an hydraulic ram having a cylinder portion provided with a base having a pivot bore extending transversely therethrough; 'an hydraulic pump on said frame having a pivot extension provided with a transverse pivot bore, there being a duct for hydraulic uid extending from said pump and in communication with said bore of said pivot extension and there being a duct extending from theV bore'oi the cylinder base to said cylinder; and a PWt Pin Support-ed ifallvrey Qf the flame and extending' through said bares, Sad .pin having fluid ducts therein" shared and positioned to transmit fluid `from the pump extension duct to the cylinder base duct in any position of pivotal movement of the cylinder.v Y

6- In' an hydraulic jaar; .a Supporting frame; an hydraulic ram having a cylinder provided with a cylinder boreand with a base having a transyerse :pivot Ybore extending transversely therethrough. there being a passage formed in said Lcylinder affording communication between the cylinder bore and the transverse pivot bore; an

hydraulic pump on said frame having a body cylinder base Vand pump extension pivot bores,

said pin being formed with a passage shaped and positioned to transmit fluid from the pump extension passage .to the cylinder base passage in any position of pivotal ymovement of the cylinder.

7. In an hydraulic jack: a supporting frame; an 'hydraulic ram bhaving a cylinder provided with a bore and with a projecting end portion; an hydraulic pump carried by said frame, said pump having a body formed with a projecting portion, the projecting portion of said cylinder being pivotally connected to the projecting body portion of said pump, there being a passage formed in said cylinder body communicating with the cylinder bore and'extending within the projecting end portion of said cylinder, and there being a iluid outlet passage formed in said pump body and extending within the projecting body portion of said pump; and means including a conduit embodied in said pivotal connection and aording communication between the passages in the projecting portions of said cylinder and pump body for conducting fluid under pressure from said pump to said cylinder bore.

EDWARD H. SCHULTZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,819,378 Nilson Aug. 18, 1931 1,873,473 Pfauser Aug. 23, 1932 2,085,720 Nilson June 29, 1937 2,151,057 Suth Mar. 21, 1939 2,430,872 Grudin Nov. 18, 1947 2,435,326 Schwerin Feb. 3, 1948 2,479,679 Grime Aug. 23, 1949 

